In the movie P Storm, William Luk is a senior officer of the ICAC (Independent Commission Against Corruption) who is known for his tenacity and success in taking down corrupt officials in Hong Kong. After receiving a tip-off from Liu Yue Ping about Cao Yuen Yuen's corrupt activities, Luk and his team decide to devise a plan to catch her in the act.
They come up with a daring plan for Luk to infiltrate the prison as an inmate, posing as a low-level criminal who can help Cao with her bribes. Once inside, Luk befriends Cao and gains her trust, as well as that of her gang members and the corrupt HKCS officers who are facilitating her bribes.
Despite the danger of being discovered and the harsh conditions of prison life, Luk persists in his investigation. He learns that Cao is not only bribing officers to get special treatment, but is also involved in illegal drug trafficking and other criminal activities.
As Luk uncovers more evidence of Cao's crimes, he realizes he must use all his skills and resources to bring her down. With the help of Ching Tak Ming and Chief Inspector Lau Po-keung, who are coordinating the operation from outside the prison, Luk attempts to gather enough evidence to arrest Cao and her co-conspirators.
However, Cao is a shrewd opponent, and she senses that something is amiss. As the tension builds and the stakes get higher, Luk and his team must race against time to complete their investigation and bring Cao to justice, before she can escape or the corrupt officials can cover up their crimes.
